Implantable medical devices for multi-chamber pacing

Abstract

Systems, devices, and methods may be used to deliver and provide cardiac pacing therapy to a patient. Leads or leadlets carrying one or more left ventricular electrodes may be positioned in or near the interventricular septum to sense and pace left ventricular signals of the patient's heart. In one example, a leadlet including one or more left ventricular electrodes may extend in the coronary sinus from a leadless implantable medical device located in the right atrium.

What is claimed is: 
     
         1 . An implantable medical device comprising:
 a plurality of electrodes comprising:
 a right atrial electrode positionable within the right atrium to deliver cardiac therapy to or sense electrical activity of the right atrium of the patient's heart; and 
 at least one left ventricular electrode positionable proximate the left ventricle of the patient's heart to deliver cardiac therapy to or sense electrical activity of the left ventricle of the patient's heart; 
   a housing extending from a proximal end region to a distal end region, wherein the right atrial electrode is leadlessly coupled to the proximal end region;   a leadlet extending from a proximal region to a distal region, wherein the proximal region is coupled to the distal end region of the housing and the at least one ventricular electrode is coupled to the distal region of the leadlet, wherein the leadlet is configured to extend through the coronary sinus ostium and into the coronary sinus or a coronary vein of the patient's heart to position the least one left ventricular electrode proximate the left ventricle of the patient's heart;   a therapy delivery circuit within the housing and operably coupled to the plurality of electrodes to deliver cardiac therapy to the patient's heart;   a sensing circuit within the housing and operably coupled to the plurality of electrodes to sense electrical activity of the patient's heart; and   a controller within the housing and comprising processing circuitry operably coupled to the therapy delivery circuit and the sensing circuit, the controller configured to:
 monitor electrical activity using the processing circuitry and one or more of the plurality of electrodes; and 
 delivering pacing therapy using the processing circuitry and one or more of the plurality of electrodes. 
   
     
     
         2 . The device of  claim 1 , wherein the at least one left ventricular electrode is implantable into the left ventricular myocardium from the coronary sinus proximal to the posterior vein of the patient's heart. 
     
     
         3 . The device of  claim 1 , wherein the at least one left ventricular electrode is implantable into the anterior interventricular vein of the patient's heart. 
     
     
         4 . The device of  claim 1 , wherein the at least one left ventricular electrode is implantable into the lateral vein of the patient's heart. 
     
     
         5 . The device of  claim 1 , wherein delivering pacing therapy comprises utilizing field steering to avoid left atrial capture by the at least one left ventricular electrode. 
     
     
         6 . A method comprising:
 implanting a right atrial electrode in the right atrial endocardium or in the right atrial myocardium of a patient's heart, the right atrial electrode being leadlessly coupled to a proximal end region of an implantable housing, wherein processing circuitry is disposed in the housing and operably coupled to the right atrial electrode;   implanting at least one left ventricular electrode through the coronary sinus ostium and into the coronary sinus or a coronary vein of the patient's heart, the at least one left ventricular electrode being coupled to a distal region of a leadlet, a proximal region of the leadlet being coupled to a distal end region of the implantable housing, wherein the processing circuitry is operably coupled to the at least one left ventricular electrode;   monitoring electrical activity using the processing circuitry and one or more of the right atrial electrode and the at least one left ventricular electrode; and   delivering pacing therapy using the processing circuitry and at one or more of the right atrial electrode and the at least one left ventricular electrode.   
     
     
         7 . The method of  claim 6 , wherein implanting the left ventricular electrode comprises implanting the left ventricular electrode into the left ventricular myocardium from the coronary sinus proximal to the posterior vein of the patient's heart. 
     
     
         8 . The method of  claim 6 , wherein implanting the left ventricular electrode comprises implanting the left ventricular electrode into the anterior interventricular vein of the patient's heart. 
     
     
         9 . The method of  claim 6 , wherein implanting the left ventricular electrode comprises implanting the left ventricular electrode into the lateral vein of the patient's heart. 
     
     
         10 . The method of  claim 6 , wherein delivering pacing therapy comprises utilizing field steering to avoid left atrial capture by the left ventricular electrode. 
     
     
         11 . A method comprising:
 delivering a delivery catheter and a penetration element disposed in the delivery catheter to the right ventricular endocardium of the interventricular septal wall of a patient's heart;   puncturing the right ventricular endocardium using the penetration element to form an opening through the right ventricular endocardium and into the interventricular septal wall;   retracting the penetration element;   advancing a distal portion of a guide element through the delivery catheter and the opening and into the interventricular septal wall to extend along the left ventricular endocardial wall; and   delivering a distal portion of an implantable medical lead over the guide element to the left ventricular myocardium to extend along the left ventricular endocardial wall to position at least one left ventricular electrode on the distal portion in the left ventricular myocardium.   
     
     
         12 . The method of  claim 11 , wherein the at least one left ventricular electrode is positioned proximate to the left bundle branch of the conduction system of the patient's heart. 
     
     
         13 . The method of  claim 11 , further comprising implanting at least one right ventricular electrode proximate to the right ventricular endocardium, the at least one right ventricular electrode being positioned proximal to the at least one left ventricular electrode on the distal portion of the implantable medical lead. 
     
     
         14 . The method of  claim 13 , further comprising:
 monitoring electrical activity of at least one of the at least one right ventricular electrode and the at least one left ventricular electrode; and   delivering pacing therapy using at least one of the at least one right ventricular electrode and the at least one left ventricular electrode.   
     
     
         15 . The method of  claim 14 , wherein delivering pacing therapy comprises delivering pacing pulses using the at least one left ventricular electrode to the left bundle branch of the conduction system of the patient's heart. 
     
     
         16 . The method of  claim 13 , wherein the at least one left ventricular electrode comprises a plurality of left ventricular electrodes, wherein the at least one right ventricular electrode comprises a plurality of right ventricular electrodes. 
     
     
         17 . The method of  claim 11 , wherein the delivery catheter extends from a proximal portion to a distal portion, wherein the distal portion defines a curvature to position a distal end of the catheter substantially flush to the right ventricular endocardium. 
     
     
         18 . The method of  claim 11 , wherein the guide element extends from a proximal region to the distal region, wherein the distal region comprises a distal curvature portion that curves when exiting the delivery catheter into the interventricular septal wall so as to deliver at least a region of the distal portion of the implantable medical lead substantially parallel to the interventricular septal wall in the left ventricular myocardium. 
     
     
         19 . A system for delivering an implantable medical lead into the interventricular septal wall and proximate the left ventricular myocardium, the system comprising:
 a delivery catheter extending from a proximal end region to a distal end region, the distal end region positionable adjacent to the right ventricular endocardium of the interventricular septal wall of a patient's heart;   a penetration element disposable in the delivery catheter to form an opening through the right ventricular endocardium and into the interventricular septal wall; and   a guide element extending from a proximal end region to a distal end region, the guide element disposable in the delivery catheter to enter the interventricular septal wall through the opening and to extend along the left ventricular endocardial wall.   
     
     
         20 . The system of  claim 19 , wherein the system further comprises an implantable medical lead comprising at least one left ventricular electrode and deliverable over the guide element to the left ventricular myocardium to extend along the left ventricular endocardial wall to position the at least one left ventricular electrode in the left ventricular myocardium of the patient's heart. 
     
     
         21 . The system of  claim 20 , wherein the at least on left ventricular electrode is positioned proximate to the left bundle branch of the conduction system of the patient's heart. 
     
     
         22 . The system of  claim 20 , where the implantable medical lead further comprises at least one right ventricular electrode positionable proximate to the right ventricular endocardium. 
     
     
         23 . The system of  claim 22 , wherein the at least one left ventricular electrode comprises a plurality of left ventricular electrodes, wherein the at least one right ventricular electrode comprises a plurality of right ventricular electrodes. 
     
     
         24 . The system of  claim 19 , wherein the distal end region of the delivery catheter defines a curvature to position a distal end of the catheter substantially flush to the right ventricular endocardium. 
     
     
         25 . The system of  claim 19 , wherein the distal end region of the guide element comprises a distal curvature portion that curves when exiting the delivery catheter into the interventricular septal wall so as to deliver at least a region of the distal portion of the implantable medical lead substantially parallel to the interventricular septal wall in the left ventricular myocardium.